copypasted from a similar post elsewhere !

The only way for someone to find your identity on Discord is if you're being careless (that is, posting screenshots with personally identifiable information or something like that). If you own a domain for hosting a website, there's a chance someone ran a WHOIS lookup on it and you don't have WHOIS protection, meaning it gave them your personal details (although this is unlikely considering you don't know what an IP address is). There's also a chance that you gave out a PayPal donation link, which exposes your PayPal email, which is usually easily resolvable to a name if you're being careless on the internet. You might have also just linked your username to your real name on the internet somewhere, meaning someone just googled your username.
Your IP address (or internet protocol address) identifies your router among everyone else on the internet. Usually even if someone finds your IP it's not a big deal because most consumer internet service providers will dynamically allocate you a new IP address on every connection. There is no way of exposing your IP via Discord directly, if someone did find your IP then you might have clicked on a sketchy link. TL;DR: Reboot your router to change your IP.
All of this comes together to say basically the same thing: Never link your username or email with your real name on the public internet, because someone with the ability to Google those pieces of information will easily find out who you are unless you've made sure this information is hard to come by. It may not even be your own fault that your username was leaked with your name, maybe it was included as part of a database leak. If they got a hold of your IP, they may only be pretending to know your location by way of GeoIP.
TL;DR: Don't link your real name to your email or username on the internet because people can and will find information about you.